Long live the virus

In post elemntary school, a virus meant something that eats up another thing forcefully. I junior high it was- Plasmodium is a malaria protozoon (virus), so is Influenza. In university it was a program that could do anything without getting caught. It could be of any form - a trojan horse, a worm (a smaller version of a virus (hehehe)). Now, it's like, Why the hell is my system, at work not getting infected with that stuff! Yes... its like that... I dont have an antivirus S/W installed, and I open every goddamn mail possible (at work ie., not at home) but I can't get a freaggin' virus attack!
I want to.... badly.